Grate bar



y 1933- J. 5. THOMPSON GRATE BAR Filed March 28. 1930 FNVEN ATTORNEY Patented .luly 11, 1933 PATENT OFFICE *7 rnorirson, or new noonnnnn, new Yon-K, assrsnoa TO manners consona- T101210}? ctnvnrann, or -re, A coaronarron or DELAWARE snare Baa Application filed March 28, 1930. Serial No. 439,5t6.

Jhis invention relates to grates of the type used in locomotive fire boXes, marine boiler furnaces, and for other similar heavy duty purposes. More particularly, the invention is concerned with a grate bar having various novel features of construction by virtue of which fuel may be burned more eficiently thereon with the formation of a fine ash without clinl-zers; The invention will be described in a form appropriate for use in a locomotive, but it is to be understood that the utility of the invention is not limited to that particular use, which is described merely for purposes of illustration.

Owing to the increasing demands that have been made by railroads on motive power, the tendency in locomotive construction is to increase the size and weight and to build bigger fire boxes, with correspondingly heavier grates and grate frames. As additional weight has been placed on the locomotive by reason of the provision of such appliances as feed water heaters, superheaters, andthe like, some of the larger locomotives have closely approached the limit of weight imposed by the stren th of bridges, road bed, Attention has, therefore, been directed o the lightening of the grate structure and some locomotives, the usual cast iron grate bars and grate frames heretofore in common use have been replaced by bars and frames of steel. Steel grate bars are much'lighter in weight than cast iron for the'same surface area, but such bars, when subjected to high fire box temperatures, have a tendency to sag under the weight of the fuel. The cost of initial installation of steel bars is greater than ofcastiron and the replacement and repair charges are also much greater by reason of the frequent sagging of the bars in service.

The-present invention is accordingly directed to the provision of a grate bar of novel construction which is much lighter in weight than bars of the same metal oft-he construction heretofore commonly used. This-bar may be made either in cast iron or steel as may be preferred, andineither case has a longer life than standard bars by reason of the fact that thenew bar is formedwith I slots of Zig-Zag shape betweenthem.

means by which 'the bar can be ventilated and kept cool during operation. The new bar also provides more efficient combustion by reason of a better distribution of air to the fuel carried thereon, the ventilating means also providing for the flow of air to the fuel as well as serving as a coolingmeans.

The new grate .bar consists of a carrier member and a. plurality of fuel-supporting units extending beyond the lateral edges thereof, these units bei-ngeither removable from the carrier or integral therewith as. may be; desired, the removable construction being prefe redr Each of the fuel-supporting units consists of a plate provided with rows of spaced lugs projecting from its opposite faces,'the lugs on one face being. staggered with respect to those on the opposite face. cavity extends through the plate 1 and lntoeach lug, form ng a chamber in the lug into which air may enter through the plate. An opening from the cavity through the top of the unit furnishes an outlet from the chamber and air can flow through the passage consisting of the entrance opening, the chamber, and the outlet opening, directly to fuel being burned 011 top of the plate. This insures a wide distribution of air, light ens th-e'weight, and keeps the unit cool.

Then the units are mounted on the carrier bar, the lugs of each unit enter the spaces betweenthe lugs of the adjacentunits and the units form a substantially continuous fuel-supporting surface with only small form distribution of the. air throughout the surface of the grate is thus obtained, and

the formation of blow holes is prevented.

F or a better understanding of the invention, reference may be had to the accompanyingdrawing in which Fig; 1 is a sectional view of the new bar showing a removable unit thereon;

Fig. 2 isa fragmentary plan view showing portions of two units on a bar; I

3 is a sectionalview of theremovable unit on the line 33 of Fig. l; a

r Fig. l is a view of the unit in side elevation; and f A unijection.

spaced areas of small size and air, can reach 7 usual trunnions 15 and it has a shaker arm- 16 extending downwardly for connection to the usual shaker rod. The bar is mounted in the fire box with its trunnions 15 received in sockets in frame members 17. r In the ordinary locomotive firebox, there are two side frame members 17 and a center member, not illustrated, so that each grate bar is supported on its trunnions in a side frame member and a center frame member.

Mounted on the carrier bar are fuelsupporting units, each of which includes a plate 18 from opposite faces of which project hollow lugs 19. Each lug is formed with an air passage 20 extending upwardly in its outer edge and there is a cavity 21 in the face of the plate opposite to each lug, extend ing into the lug, so that the lug is formed with a chamber 22 which opens laterally through the plate. Inthe top of the plate and communicating with the chamber is an air, exit opening23 so that air may enter the tions being separated by air channels 25 and 26. The top 27 of each projection provides a fuel-supporting surface which is substantially less in area than the base of the pro- Thus, the fuel is in contact with projections 281) on the end of a lug on the unit B. The size of these projections determines the space between the two units and it will be observed that there is an air passage 29 between the two units, which passage has offset portions and a generally zig-zag shape. The width of the passage 29 depends on the size of the spacing projections 28 and with the lugs of the two adjacent units interfitting, there is no straight passage across the grate bar but on the contrary this passage is broken up'in the manner indicated. lVith this arrangement, air which flows up between a pair of units on the carrier reaches widely spaced portions of the fuel bed and a better distribution of air is provide with consequent more eflicient combustion.

Whenv the new type of grate bar is employed, it is preferable to use a grate frame which is provided with lugs 30 on its inner edge, which lugs enter between similar lugs on the end unit on the cross-bar, as shown in Fig. 5. The lugs 30 on the grate frame are so formed that the interfitting of the lugs on the end unit with those on the frame does not interfere with the shaking of the grate bar in the ordinary way.

Vhen the units of the grate bar are made removable, I prefer to employ the construction shown in Fig. 1. Each plate in the form there illustrated is provided with a recess 31 in its lower edge having a shape generally corresponding to the section of the carrier bar, the top of the recess being larger than the flange 12 so that the unit rests on the flat top surfaces 82 and 33 of the web 11. At the bottom of the recess are formed spaced lugs 34 and the distance between these lugs is slightly greater than the overall width of the web 11, thus permitting the units to be placed on the carrier bar by a movement transverse to the length thereof.-

With the arrangement described, the units have a slight freedom of movement relative to the carrier bar and when the latter is rocked in the ordinary way, one end, for example 35, of the web forms a pivot about which the carrier member swings relative to theunit, the unit being raised slightly but not rocking. The weight of the fuel on the unit maintains the unit stationary during this slight rocking of the carrier bar.

The relative movement continues until the flange 12 binds in the top of the recess 31 and if the rocking of the carrier bar is continued until the binding occurs, further rocking causes a. rocking movement of the unit with the carrier bar. 011 return movement of the carrier bar, the unit is moved back to its orignal position and then the relative movement of the carrier bar and unit commences again until the surface 36 of the webll, which has been separated from the inner wall of the recess in the unit, strikes that wall a sharp blow. This jars the unit and has a tendency to free fine ash which may have collected thereon. The ash slides toms of which are suitably inclined for the purpose, and the ash passes into the air passages and then falls down through the grate into; the ash pan. Y

Since the lugs 34 at the bottom of the recess are spaced apart a distance only slightly greater than the overall width of the web 11, relative movement of the units and carrier bar causes one or the other of the lugs to' engage beneath the edge of the web so that the units are locked in place thereon and cannot be accidentally dislodged during the shaking operation. 'The locking action takes eifect only during the shaking of the grate and when the bars are in normal position, as illustrated in Fig. 1, any unit of any bar be readily removed by being lifted free of the bar. This simplifies installation and should any single unit of the grate be injured in service, it can be removed and a new one substituted for it without dismantling the entire grate bar in which the unit is mounted.

In this grate, due to the more efficient combustion, the fuel is burned to a fine ash without the formation of clinkers of substantial size and as a consequence, the fuel bed may be kept clean by only a slight shaking action of the grate sufiicient to cause the units to be jarred rather than rocked. In this way, live coals are not discharged into the ash pan as is frequently the case with ordinary ars.

By reason of the lightening of the new grate bar in the manner described,this bar when made of cast iron has a weight substantially less than a standard bar of that metal and the lightening effect is produced with-- out weakening the bar. When made of steel, the new bar is lighter than a standard steel. bar and at the same time has a longer life. The ventilation of the bar in the manner described prevents it from heating to the point where sagging or distortion would occur.

1. A grate bar which comprises a longi tudinal member, and fuel supporting units extending beyond the side edges of said member, each unit comprising a plate and lugs projecting from the sides of the plate alternately in opposite directions, each lug having an air chamber in it provided with an inlet opening through the face of the plate and s an outlet opening at the top.

'2. A grate bar which comprises a longitudinal member, and fuel supportin units extending beyond the side edges of sai member, each unit comprising a plate and a row of lugs projecting from each face of the plate, the lugs on opposite faces of the plate being staggered and each lug having an air chamber in it with an inlet opening through the face of the plate and an outlet opening at the top.

3. A grate bar which comprises a longitudinal member and fuel supporting units extending beyond the side edges thereof, each unit having lugs projecting from oppo-- site faces thereof with the lugs from one face offset from those from the other, and the lugs of one unit interfitting with those of the adjacent unit, each lug having an air chamber in it with an inlet opening through the face of the plate and an outlet opening at the top.

4. In a grate bar, a fuel supporting unit comprising a plate and rows of spaced lugs projecting from opposite faces of said plate, the lugs of the two rows being staggered, each lug having a plurality of air channels at its top producing a plurality of small fuel supporting areas, and'an air chamber in said lug having an inlet opening through the opposite face of said plate and an outlet opening at its top and leading to said channels. V

In testimony whereof I affix my signature.

JAMES s. THOMPSON. 

